////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2017-2021 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// This file is part of Octave.
//
// Octave is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Octave is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Octave; see the file COPYING.  If not, see
// <https://www.gnu.org/licenses/>.
//
////////////////////////////////////////////////////////////////////////

// Extracted from urlwrite.cc.

#if ! defined (octave_url_handle_manager)
#define octave_url_handle_manager 1

#include "octave-config.h"

#include <cmath>

#include <map>
#include <set>

#include "lo-mappers.h"

#include "oct-handle.h"
#include "url-transfer.h"

namespace octave
{
  typedef octave_handle url_handle;

  class OCTINTERP_API url_handle_manager
  {
  public:

    url_handle_manager (void)
      : m_handle_map (), m_handle_free_list (),
        m_next_handle (-1.0 - (rand () + 1.0) / (RAND_MAX + 2.0)) { }

    url_handle_manager (const url_handle_manager&) = delete;

    url_handle_manager& operator = (const url_handle_manager&) = delete;

    ~url_handle_manager (void) = default;

    url_handle get_handle (void);

    void free (const url_handle& h);

    url_handle lookup (double val)
    {
      iterator p = (math::isnan (val) ? m_handle_map.end ()
                                      : m_handle_map.find (val));

      return (p != m_handle_map.end ()) ? p->first : url_handle ();
    }

    url_handle lookup (const octave_value& val)
    {
      return val.is_real_scalar () ? lookup (val.double_value ())
                                   : url_handle ();
    }

    url_transfer get_object (double val)
    {
      return get_object (lookup (val));
    }

    url_transfer get_object (const octave_value& val)
    {
      return get_object (lookup (val));
    }

    url_transfer get_object (const url_handle& h)
    {
      iterator p = (h.ok () ? m_handle_map.find (h) : m_handle_map.end ());

      return (p != m_handle_map.end ()) ? p->second : url_transfer ();
    }

    url_handle make_url_handle (const std::string& host,
                                const std::string& user,
                                const std::string& passwd,
                                std::ostream& os)
    {
      url_handle h = get_handle ();

      url_transfer obj (host, user, passwd, os);

      if (! obj.is_valid ())
        error ("support for URL transfers was disabled when Octave was built");

      m_handle_map[h] = obj;

      return h;
    }

    Matrix handle_list (void)
    {
      Matrix retval (1, m_handle_map.size ());

      octave_idx_type i = 0;
      for (const auto& h_obj : m_handle_map)
        {
          url_handle h = h_obj.first;

          retval(i++) = h.value ();
        }

      return retval;
    }


  private:

    typedef std::map<url_handle, url_transfer>::iterator iterator;
    typedef std::map<url_handle, url_transfer>::const_iterator const_iterator;

    typedef std::set<url_handle>::iterator free_list_iterator;
    typedef std::set<url_handle>::const_iterator const_free_list_iterator;

    // A map of handles to curl objects.
    std::map<url_handle, url_transfer> m_handle_map;

    // The available curl handles.
    std::set<url_handle> m_handle_free_list;

    // The next handle available if handle_free_list is empty.
    double m_next_handle;
  };
}

#endif
